When Pip says that Jaggers seemed to bully his sandwich as he ate it, he is implying that Jaggers is a tough and aggressive person. The phrase "bully his sandwich" suggests that Jaggers is using force or intimidation to dominate or control the sandwich, which could be seen as a metaphor for his behavior towards other people or things. This characterization of Jaggers as tough and aggressive is consistent with other descriptions of him in the novel, and suggests that he is a formidable and intimidating presence.